Language Disorders - University of Florida

Language Disorders
Medical and Psychosocial Aspects
of Disability
11/2/04
Communication
 There are 3 elements in this exchange,
and all must be present:
1. Message
2. Message
must be expressed
3. Message must be understood
Speech and Language
 Speech is the motor act of
communicating by articulating verbal
expression
 Language is the knowledge of a symbol
system used for interpersonal
communication.
Four domains of language
 Phonology
 Grammar
 Semantics
 Pragmatics
Phonology
 The ability to produce and
discriminate the specific sounds of a
given language.
 Its unit, the phoneme, is characterized
by distinctive features.
 Babies start discriminating phonemes
during the first few months of life, and
they produce them soon after.
Phonology
 Phonological receptivity is pluripotential
at birth
 Starts to decay at around 10 months
 Reaches a rather general inability to
acquire native phonology by
preadolescence
Grammar
 The underlying rules that organize
any specific language.
 The combinatorial rules that most native
speakers of a language recognize as
acceptable for that language and that
allow a native speaker an infinite array
of generative possibilities.
Grammar
 Composed of both morphology and
syntax.
Semantics
 The study of meaning
 Includes the study of vocabulary
(lexicon).
Lexicon
 Lexical entries are organized in the
mental dictionary according to welldefined rules
 Allows the young child to acquire a peak
average of 10 new words per day.
 By 24 months the average child knows
50 words.
Lexicon Growth
 The subsequent
exponential growth
makes it difficult to
determine
vocabulary size with
exactitude.
Environmental factors
predicting large vocabularies
 Reading and discussing children's stories
 The quality of dinner table conversations
 Large mother-produced number of words
 Higher socioeconomic status (SES)
 Being the firstborn ( Hoff-Ginsberg, 1998 )
 Quantity and sophistication of mother's
vocabulary ( Snow, 1998 ).
Pragmatics
 A number of sub-domains reflecting
communicative competence.
Sub domains of Pragmatics
 Rules of conversation (turn-taking, topic
maintenance, conversational repair)
 Politeness
 Narrative and extended discourse
 The implementation of communicative
intents
Pragmatic disorders
 Little variety in language use
 May say inappropriate or unrelated
things during conversations
 May tell stories in a disorganized way
 Can often make demands, ask
questions, and greet people
 Has trouble organizing language to talk
about what happened in the past.
Pragmatic disorders
 Appear to pull topics out of the air
 May not use statements that signal a
change in topic, such as "That reminds
me."
 Peers may avoid having conversations
with such a child.
 Can lower social acceptance.
Language Developmental
Trajectory
Telegraphic speech
Word combinations
Word production
Word comprehension
Canonical Babbling
 By age 3, most
normal children
have mastered the
basic structures of
their native
language
Language acquisition
 Occurs with uniformity and rapidity
 Supports the hypothesized existence of
innate, genetically determined Universal
Grammars
 Recently proposed a combination of
traditional learning and innate language
modules.
Disfluencies in Children
 Almost all children go through a stage of
frequent disfluency
 usually
between the ages of 2 and 5.
 Speech is produced easily in spite of
the disfluencies.
Etiology of Speech &
Language Disorders
 Mental retardation
 Bilingualism
 Hearing loss
 Psychosocial
 Maturation delay
(developmental
language delay)
 Expressive
language disorder
(developmental
expressive aphasia)




deprivation
Autism
Elective mutism
Receptive aphasia
Cerebral palsy
Overview of major types of
speech disorders
 Definitions vary, but
generally agree that
speech disorders involve
deviations of sufficient
magnitude to interfere
with communication.
 They draw attention to
the speaking act and
away from the message
1. Fluency Disorders
 Speech is characterized by repeated
interruptions, hesitations, or repetitions
 Stuttering is by far the most well-known
fluency disorder
1. Fluency disorders Stuttering
 Flow of speech is abnormally
interrupted by repetitions, blocking, or
prolongations of sounds, syllables,
words, or phrases
 Very familiar, but actually quite rare –
only 1-5% of the population.
 Articulation disorders actually occur
much more frequently than stuttering
Stuttering -- Causes


1.
2.
3.
Still a mystery
Three perspectives:
Symptom of emotional
disturbance
Result of biological
makeup
Learned response
Stuttering
 Disorder of speech fluency that
interrupts the forward flow of speech.
 All
individuals are disfluent at times
 Differentiated by the kind and amount of
the disfluencies
Characteristics-Repetition
 Sounds
 b-b-b-ball
 Syllables
 mo-mo-mommy
 Parts of words
 basket-basket-basketball
 Whole words, and phrases
CharacteristicsProlongation
 Stretching, of sounds or syllables
 r-----abbit
Characteristics
 Tense pauses, hesitations, and/or no
sound between words
 Speech that occurs in spurts
 as
the child tries to initiate or maintain
voice
 Variability in stuttering behavior
 depending
on the speaking situation
Related behaviors
 tense muscles in the lips, jaw, and/or
neck
 tremor of the lips, jaw, and/or tongue
 foot tapping
 eye blinks
 head turns
2. Articulation disorders
 This is the largest category of all
speech problems
 DSM-IV calls these “phonological
disorders.”
 “abnormal speech-sound production,
characterized by inaccurate or
otherwise inappropriate execution of
speaking”
2. Articulation disorders
 Great majority are functional articulation
disorders
 Might represent as much as 80% of the
speech disorders diagnosed by speech
clinicians
 Must be very careful to distinguish true
problems from delay.
 E.g., r, s, th problems may largely disappear
naturally after 5 years of age
2. Articulation disorders
1. Omissions
2. Substitutions
3. Additions
4. Distortions
3. Voice disorders
 Unusual or abnormal acoustical
qualities in the sounds made when a
person speaks
 Very little research here
 What is a “normal” sounding voice?
 Nasality, hoarseness, breathiness
Normal Speech Development
4. Delayed speech
 Failure to develop speech at the




expected age
Somewhat subjective
Usually associated with other
maturational delays
May also be associated with a hearing
impairment, mental retardation,
emotional disturbance, or brain injury
Often the result of environmental
deprivation
Epidemiology of Speech
Delay
 Common childhood problem
 Affects 3 to 10 percent of children.
 3-4X more common in boys than in
girls.
Most common causes of
speech delay
 Mental retardation
 Hearing loss
 Maturation delay
Overview of major types of
language disorders
 Need to understand normal language
and prelanguage development
 See Table 10.1 on 320
 May involve comprehension
(understanding) or expression in
written or spoken language
 These are very complex to diagnose
and treat
Language and Brain
Language disorders
1. Expressive language disorders
2. Receptive language disorders
3. Aphasia – loss of the ability to speak
or comprehend language because of
an injury or developmental abnormality
in the brain
EXPRESSIVE LANGUAGE
DISORDER
(developmental expressive aphasia)
 Fail to develop the use of speech at the
usual age.
EXPRESSIVE LANGUAGE DISORDER
 Normal intelligence
 Normal hearing
 Good emotional relationships
 Normal articulation skills.
 Comprehension of speech is
appropriate to the age of the child
EXPRESSIVE LANGUAGE DISORDER
 Brain dysfunction
that results in an
inability to
translate ideas
into speech.
EXPRESSIVE LANGUAGE DISORDER
 The child is at risk for language-based
learning disabilities (dyslexia).
 May use gestures to supplement their
limited verbal expression .
Maturation Delay vs.
Expressive Language
Disorder?
 The late bloomer will
eventually develop
normal speech
 The child with an
expressive language
disorder will not do
so without
intervention.
Maturation Delay vs.
Expressive Language
Disorder?
 It is sometimes difficult, if not
impossible, to distinguish at
an early age a late bloomer
from a child with an
expressive language disorder.
BILINGUALISM
 A bilingual home
environment may
cause an apparent
temporary delay in
the onset of both
languages.
BILINGUALISM
 The bilingual child's comprehension of
the two languages is normal for a child
of the same age.
 Usually becomes proficient in both
languages before the age of five years.
Interference or transfer
 An English error due to the direct
influence of the primary language
structure.
 This is a normal phenomenon
Silent period
 Common second-language acquisition
phenomenon
 Often very quiet, speaking little
 Focus on understanding the new
language
 The younger the child, the longer the
silent period tends to last.
Code switching
 Changing languages over phrases or
sentences.
 Normal phenomenon
Benefits of Bilingualism
 Children who are fluent bilinguals
actually outperform monolingual
speakers on tests of metalinguistic skill.
Benefits of Bilingualism
 Our world is shrinking and business
becomes increasingly international
 Children who are fluent bilingual
speakers are potentially a tremendously
valuable resource for the U.S. economy.
Language Disorders
 Egyptians reported
speech loss after
blow to head 3000
years ago
 Broca (1861) finds
damage to left inferior
frontal region (Broca’s
area) of a language
impaired patient, in
postmortem analysis
Language Disorders (2)
 In language disorders
 90-95% of cases, damage is to the left
hemisphere
 5-10% of cases, to the right hemisphere
 Wada test is used to determine the
hemispheric dominance


Sodium amydal is injected to the carotid artery
First to the left and then to the right
Language Disorders (3)
 Paraphasia:
 Substitution of a word by a sound, an incorrect
word, or an unintended word
 Neologism:
 Paraphasia with a completely novel word
 Nonfluent speech:
 Talking with considerable effort
 Agraphia:
 Impairment in writing
 Alexia:
 Disturbances in reading
Three major types of Aphasia
Rosenzweig: Table 19.1, p. 615
 Borca’s aphasia
 Nonfluent speech
 Wernicke’s aphasia
 Fluent speech but unintelligible
 Global aphasia
 Total loss of language
Others: Conduction, Subcortical, Transcortical
Motor/Sensory (see also Kandel, Table 59-1)
Brain areas involved in Language
Broca’s Aphasia
Brodmann 44, 45
 Lesions in the left inferior frontal region
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

(Broca’s area)
Nonfluent, labored, and hesitant speech
Most also lost the ability to name persons or
subjects (anomia)
Can utter automatic speech (“hello”)
Comprehension relatively intact
Most also have partial paralysis of one side of
the body (hemiplegia)
If extensive, not much recovery over time
Wernicke’s
Aphasia
Brodmann 22, 30
 Lesions in posterior of the left superior
temporal gyrus, extending to adjacent parietal
cortex
 Fluent speech
 But contains many paraphasias

“girl”-“curl”, “bread”-“cake”
 Syntactical but empty sentences
 Cannot repeat words or sentences
 Unable to understand what they read or hear
 Usually no partial paralysis
Wernicke-Geschwind Model
1. Repeating a spoken word
 Arcuate fasciculus is the bridge from the
Wernicke’s area to the Broca’s area
Wernicke-Geschwind Model
2. Repeating a written word
 Angular gyrus is the gateway from visual cortex to
Wernicke’s area
 This is an oversimplification of the issue:
 not all patients show such predicted behavior (Howard,
1997)
Sign Languages
 Full-fledged languages, created by hearing-
impaired people (not by Linguists):



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Dialects, jokes, poems, etc.
Do not resemble the spoken language of the same
area (ASL resembles Bantu and Navaho)
Pinker: Nicaraguan Sign Language
Another evidence of the origins of language (gestures)
 Most gestures in ASL are with right-hand, or
else both hands (left hemisphere dominance)
 Signers with brain damage to similar regions
show aphasia as well
Signer Aphasia
 Young man, both spoken and sign language:
 Accident and damage to brain
 Both spoken and sign languages are affected
 Deaf-mute person, sign language:
 Stroke and damage to left-side of the brain
 Impairment in sign language
 3 deaf signers:
 Different damages to the brain with different
impairments to grammar and word production
Spoken and Sign Languages
 Neural mechanisms are similar
 fMRI studies show similar activations for
both hearing and deaf
 But in signers, homologous activation
on the right hemisphere is unanswered
yet
Dyslexia
 Problem in learning to read
 Common in boys and left-handed
 High IQ, so related with language only
 Postmortem observation revealed anomalies
in the arrangement of cortical cells


Micropolygyria: excessive cortical folding
Ectopias: nests of extra cells in unusual location
 Might have occurred in mid-gestation, during
cell migration period
Acquired Dyslexia = Alexia
 Disorder in adulthood as a result of
disease or injury
 Deep dyslexia (pays attn. to wholes):



“cow” -> “horse”, cannot read abstract words
Fails to see small differences (do not read
each letter)
Problems with nonsense words
 Surface dyslexia (pays attn. to details):
 Nonsense words are fine
 Suggests 2 different systems:
 One focused on the meanings of whole
words
 The other on the sounds of words
Electrical Stimulation
 Penfield and Roberts (1959): During epilepsy
surgery under local anesthesia to locate
cortical language areas, stimulation of:

Large anterior zone:
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Both anterior and posterior temporoparietal cortex:

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stops speech
misnaming, impaired imitation of words
Broca’s area:


unable comprehend auditory and visual semantic
material,
inability to follow oral commands, point to objects, and
understand written questions
Studies by Ojemann et al.
 Stimulation of the brain of an English-
Spanish bilingual shows different areas
for each language
 Stim of inferior premotor frontal cortex:

Arrests speech, impairs all facial movements
 Stim of areas in inferior, frontal,
temporal, parietal cortex:

Impairs sequential facial movements,
phoneme identification
 Stim of other areas:
 lead to memory errors and reading errors
 Stim of thalamus during verbal input:
 increased accuracy of subsequent recall
Williams Syndrome
 Caused by the deletion of a dozen genes
from one of the two chromosomes
numbered 7
 Shows dissociation between language
and intelligence, patients are:


Fluent in language
But cannot tie their shoe laces, draw images,
etc.
 Developmental process is altered:
 Number skills good at infancy, poor at
adulthood
 Language skills poor at infancy, greatly
improved in adulthood
Lateralization of the Brain
 Human body is asymmetrical: heart,
liver, use of limbs, etc.
 Functions of the brain become
lateralized
 Each hemisphere specialized for
particular ways of working
 Split-brain patients are good examples
of lateralization of language functions
Lateralization of functions
(approximate)
 Left-hemisphere:
 Sequential analysis
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
Analytical
Problem solving
 Right-hemisphere:
 Simultaneous analysis
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Visual-Spatial skills
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Language
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Cognitive maps
Personal space
Facial recognition
Drawing
Emotional functions



Synthetic
Recognizing emotions
Expressing emotions
Music
Split-brain
 Epileptic activity spread from one hemisphere
to the other thru corpus callosum
 Since 1930, such epileptic treated by
severing the interhemispheric pathways
 At first no detectible changes (e.g. IQ)
 Animal research revealed deficits:


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Cat with both corpus callosum and optic chiasm
severed
Left-hemisphere could be trained for
symbol:reward
Right-hemisphere could be trained for inverted
symbol:reward
Left vs. Right Brain
 Pre and post operation studies showed that:
 Selective stimulation of the right and left hemisphere
was possible by stimulating different parts of the body
(e.g. right/left hand):
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Thus can test the capabilities of each hemisphere
Left hemisphere could read and verbally
communicate
Right hemisphere had small linguistic capacity:
recognize single words
Vocabulary and grammar capabilities of right is far
less than left
Only the processes taking place in the left
hemisphere could be described verbally

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